Devices currently exist for conducting spectral analysis. One such device is the monochromator. As described in U.S. Pat. No. 3,888,590, a monochromator includes an entrance slit for admitting light from a source, a collimator such as a mirror, a diffraction grating or other dispersing element and a telescope mirror for forming a substantially monochromatic image of the entrance slit. Light entering the entrance slit is reflected by the collimator, is dispersed into a spectrum by the dispersing element, and is reformed into the dispersed image by the telescope so that by positioning a receiving element such as an exit slit relative to the dispersed element, a selected portion of the spectrum is obtained. In these devices, the dispersing element customarily is movable relative to the other optical components in order to change the angle of the light and thereby produce dispersed images of different portions of the spectrum. It also should be noted that components of these devices are configured such that the light path is generally M-shaped. One of the disadvantages of these devices is that relatively complex and/or expensive mechanisms are required for movement of the diffractive element.
Another optical device for reproducing portions of the spectrum utilizes multiple monochromatic light sources, each of a different wavelength. A disadvantage of this approach is that each light source must be calibrated to ensure that the light output has the wavelength desired. The device also is relatively expensive.
Another disadvantage of certain optical devices is the use of a linear CCD, which incorporates a plurality of detectors, each of which detects energy of a particular wavelength. While such a component provides an efficient solution for simultaneously detecting a plurality of energy signals, its cost is much greater than that of a detector that can detect only a single signal at any given time.